The objectives of this study are to study the processes of bone failure and subsequent repair. The mechanism of histological and biomechanical repair from tensile yielding and compression induced shear failure will be investigated. Histological repair will be correlated with biomechanical repair for bones which have been weakened with macroscopic discontinuities, such as various type of drill holes and screws. The long term effects on bone strength of retention of internal fixation devices will also be studied. Standard histological techniques as well as standard biomechanical torsion and bending tests will be utilized in this investigation.